1. Technical Field
The present disclosure relates to a display apparatus having a touch panel, and more particularly to a display apparatus having a touch panel with a speaker function.
2. Discussion of the Related Art
Generally, a touch panel is used in an image display device such as, for example, a liquid crystal display (LCD) device. A touch panel can be used in place of or in combination with other input devices such as, for example, a keyboard or a mouse. The touch panel can sense positional coordinates of a finger of a user or an object pointing to a letter or an image displayed on an image display device.
There are various operating methods for a touch panel such as, for example, a capacitive overlay technology, a resistive overlay technology, an infrared beam technology, a surface acoustic wave technology, or a piezoelectric effect technology.
According to a resistive overlay technology, transparent electrodes are formed on two transparent supporting substrates. The transparent electrodes face with each other in a fixed interval. An air gap is formed between the transparent electrodes to prevent an electrical short. When an electric current flows to the transparent electrodes, a voltage is applied to each of the transparent electrodes due to resistance of the transparent electrodes. When a finger contacts the supporting substrate, the two transparent electrodes contact with each other. As a result, the resistance of the two transparent electrodes varies due to a parallel connection of the two transparent electrodes, and a voltage applied to the two transparent electrodes varies due to current flowing between the two transparent electrodes. Therefore, a touched position may be detected through a variation of the voltage.
A speaker used in a portable electric device, such as, for example, a cellular phone, personal digital assistant (PDA), and portable media player (PMP) converts an electric signal into a sound through a method employed by a conventional speaker. According to a method employed by a conventional speaker, a sound is converted into an electric signal and the electric signal is transferred to a speaker through an electric wire or an electric wave. The speaker oscillates air with a diaphragm and the oscillation of the air regenerates and transmits the sound. In this process, the conventional speaker requires a large volume and a particular shape such as, for example, a cone and an oval to cause resonance. A manufacturing process for the conventional speaker may be performed at a high temperature when the speaker includes ceramic material. Further, in a conventional technology, a touch panel and a speaker are formed separately.